Hydraulic pull bushing for broaching machines



Dec. 22, 1931. D. H. WEST HYDRAULIC PULL BUSHING FOR BROACHING MACHINESFiled Aug. 8, 1929 Patented Dec. 22, 1931 U N H T T S PATENT FFEGEDONALD E. WEST, OF NEW LONDON, CONNECTICUT. ASSIGNOR 'lO LAPOIIN'TEINLA- OmNE TOOL COMPANY, OF HUDSON, MASSACHUSETTS, A CORPORATION OFMAINE Application filed August 8, 1929. Serial No. 884,393.

This invention relates to a pull bushing particularly designed for usein a broaching machine in which the return movement of the broach isaccomplished at increased speed by the application of hydraulicpressure.

It is the object of my present. invention to provide means by which theapplication of hydraulic pressure also unlocks or releases the broach atthe beginning of the return my stroke, so that the broach may be removedduring or after the return stroke, as desired by. the operator.

My invention further relates to arrangements and combinations of partswhich will be hereinafter described and more particularly pointed out inthe appended claims.

A preferred form of the invention is shown in the drawings in which Fig.1 is a side elevation of my improved as hydraulic pull bushing;

Fig. 2 is a plan view thereof;

Fig. 3 is an end elevation, looking in the direction of the arrow 3 inFig.4, and

Figs. 4 and 5 are detail views of certain 25 parts to be described.

Referring to the drawings, T have shown my improved pull bushing ascomprising a head 10 formed in two parts separable along longitudinallines and secured together by 30 clamping screws 11. The head 10 isprovided with a shank 12 adapted to be inserted in a threaded opening incross head 14 and retained therein by a 100 nut 15. The end of a tubularpull shaft 16 is also threaded in 35 the cross head 14 and is retainedin position by a lock nut 17.

'A plug 18 is secured in the end of the pull shaft 16 and in effectforms one end of a pressure cylinder 20 within the shaft 16. The

40 shank 12 of the head 10 is provided with an axial recess in which apush rod 22 is slidable, and the plug 18 in the shaft "16 is alsoprovided with an axial recess 24 and. a conical end opening 25 toreceive a headed stud-or 45 sliding plunger 27.

A cross pin is pivoted at 31 in the'head 10 and .is provided with aball-shaped hearing portion 32 and with a handle portion 33. Theball-shaped portion 32 is positioned in an opening 35 in a cam plate 36'(Fig. 5), slidably secured to the top of the head 10 by studs 37 Theplate 36 is provided with inclined cam surfaces 38 adapted to engagestuds 40 mounted in swinging arms 41 and projecting downward therefrom.A sprin 42 is connected between the studs 40 and draws the arms 41yieldingly toward each other.

The arms 41 are non-rotatably secured to the upper end of cross shafts44 (Fig. 4) each having dogs 45 formed integral therewith. These dogs 45are positioned to swing transversely in openings 46 extendingtransversely through the head 10.

The head 10 is provided with an axial opening to receive the shank of abroach B, and ends of the dogs 45 normally extend into recesses 50 inthe sides of the shank broach, with the ends of the dogs positioned toengage the under side of the head 52 of the broach at the beginning ofthe working stroke.

As the broach reaches its extreme right hand position at the end of theworking stroke, (as viewed in the drawin s) hydraulic pressure isapplied in the cylinder 20 to reverse the direction of movement andactuate the broach at increased speed on its idle or return stroke. Y

As soon as pressure is applied in the cylinder 20, the piston 27 isforced to the left in Fig. 1, engaging the plunger 22 and forcing thesame against the cross pin 30, which in turn moves the cam plate 36 andcauses the same to engage and forcibly separate the studs 40 and arms41. Such movement of the arms swings the dogs 45 outward to inoperativeposition.

During the final portion of the movement of the cam plate 36, the studs40 engage the parallel outer side surfaces of the plate 36 and the dogsare thus locked in inoperative position during the removaland-replacement of the broach. After the broach is replaced and thepressure is relieved in the cylinder 20,

the broach isautomatically released by the same hydraulic pressure whichcauses return movement thereof and by which the broach remains inunlocked position until manual withdrawal of the cam plate 36. The plate36 may also be moved manually to separate the dogs and release thebroach whenever desired.

It will be noted that the broach is unlocked during the entire returnmovement thereof, so that the operator may remove the broach before thereturn movement is completed if he so desires.

- Having thus described my invention and the advantages thereof, I donot wish to be limited to the details herein disclosed, otherwise thanas set forth in the claims,-but wha I claim is 1. In a broachingmachine, a pull bushing comprising a head, a pair of broach-engagingdogs pivoted in said head, means to move said dogs toward each other toengage .the broach, arms fixed with res ect to said dog's, studs in saidarms, and a plate slidable between said studs and effective toseparatesaid dogs and to thereby release a broach when moved relative to saidhead.

2. In a broaching machine, a pull bushing comprising a head, a pair ofbroach-engaging dogs pivoted insaidhead, means to move said dogs towardeach other to engage the broach,

arms fixed with respect to said dogs, studs in said arms, and a doublefaced cam plate slidable between said studs and effective upon movementrelative to said head to separate said dogs and to thereby release the'broach and said cam plate having an addltional portion effective to locksaid dogs in-separated position..

3. In a broaching machine, a pull bushing 2 comprising a head, a pair ofbroach-engaging dogs pivoted in said head, means to move said dogstoward each other to engage the broach, a cam plate slidably mounted onsaid head and efiective to separate said dogs and thereby release theb-roach, automatic means including a member movable in said head uponthe application of pressure to said member and effective by such'movement to slide said cam plate on said head in one direction toseparate said dogs, and manual means to return said plate to inoperativeposition.

- 4. In a broaching machine, a pull bushing, broach-engaging dogsmounted in said bushing, a hollow cylindrical pull shaft connected tosaid bushing and in which hydraulic pressure may be applied to produce aquick return ouble faced cam plied to produce a. return stroke 'of thebushing, and automatic means," including a member slidable in said headupon the application of pressure to said member and connections betweensaid member and said dogs, to separate the dogs at the beginning of thereturnmovement of the bushing. I

6. In a broaching machine, a pull bushing comprising a head, a pair ofbroach engag ing dogs pivoted in said head, means to move said dogstoward each other to engage the broach, means to which pressure may be aplied to produce a return stroke of the bus a ing, and automatic means,including a member slidable in said head upon the application ofpressure to said member and connections between said member and saiddogs, to separate the dogs at the beginning of the return movement ofthe bushing, and to hold said dogs locked in separated position untilmanually released therefrom.

'7'. In a broaching machine, a pull bushing 5 comprising a head, a pairof broach engaging dogs pivoted in said head, means to move said dogstoward each other to engage the broach, means to which pressure may beapplied to produce a return stroke of the. bushing, and automatic means,including a member slidable in said head upon the application ofpressure to said member and connections between said member and saiddogs, to separate the dogs at the beginning of the return movement ofthe bushing, and means to manually operate said separating means.

8. In a broaching machine, a pull bushing comprising a head, a pair ofbroach engaging dogs pivoted in said head, means to move said dogstoward each other to engage the broach, means to which hydraulicpressure may be applied to produce a return stroke of the bushing, andmeans, including a member slidable in said head upon the application ofsaid hydraulic pressure to said member and connections between saidmember and said dogs. to simultaneously separate said dogs to releasethe broach at the beginning of the return movement of the bushing.

applied to produce a return stroke of the bushing, and means, includinga member slidable in said head upon the application of said hydraulicpressure to said member and connections between said member and saiddogs,

to simultaneously separate said dogs to release the broach at thebeginning of the return movement of the bushing, and means to hold saiddogs in separated position after the hydraulic pressure has beenrelieved.

In testimony whereof I have hereunto affixed my signature.

DONALD H. WEST.

